Telegraph signaling system



Aug 11, 1925. 1,548,873

J. M. FELL TELEGRAPH SIGNALING SYSTEM Filed Marbh 15, 1920 IN VEN TOR.

ATTORNEY Patented Aug. H, 1925. Y

L tum-en STATES JOHN M. FELL, OF HAGKEIN'SQB.GK, NEW JERSEY, ASSIGNOB TO AMERICAN TmEPHONE AND TELEGRAPH COMPANY, A CORPORATION OF NEW YORK.

TELEGRABH SIGNALING SYSTEM.

Application flied March 1-5, 1920. Serial No. 865,911.

To all whom it may concern:

Be it known that I, J OHN M. FELL, residing at Hackensack, in the county of Bergen and State of New Jersey, have invented a certain Improvements in Telegraph Signaling Systems, of which the following is a specification. l

This invention relates to telegraph signaling systems, and more particularly to 1 means for applying the duplex and half duplex methods ofoperation to local loop circuits in order to obtain greater efliciencyin the operation of the said circuits.

The practice heretofore followed in conto necting the local loop circuits. with a duplex or half duplex line circuit was to connect into the loop circuit the winding of a neutral relay which constituted the pole changer for transmitting impulses of the proper polarity to the duplex or half duplex line circuit. It

'has been found that under practical operating conditions neutral relays have a strong tendency to bias telegraph signals- It is therefore desirable to use for this purpose a polarized relay as a pole changer. One of the objects of this invention is to provide means to permit the use ofpolarized relays responsive to the operation of the keys of the loop circuit to transmit to the line cir: cuit impulses of the properlpol'arity and which will not be biased. r

Another object of this invention consists in providing means for combining the sets above referred to in order to form tele graph-repeaters which are adapted for use either as through repeaters or as terminal repeaters with sending and receiving loops to subscribers oflices.

Other and further objects ofthis invention will become apparent from the following description of the invention when read in connection with the attached drawings, of

which Figure 1 shows schematically the arrangement of the circuit for half duplex operation between two telegraph subscribers stations, Fig. 2 shows the combination of these sets to form a repeater with an inter-' mediate loop circuit, and Fig. 3 shows the combination to form-a full duplex repeater.

In'Fig. 1 are shown two telegraph substations-A and B which are connected to two repgater stations X and Y by means ofthe su vnected to windings 6 and 8 respectively.

cribers loop circuits L and L respec tively- A telegraph line circuit L, connects. the two repeater stations. The equipmentrepresented at sub-station A consists of a key K,, a neutral relay R and a battery or 1 i -ment is similar, comprising a key K,, a neutral relay R,, a battery B, and a sounder 3,.

At the repeater stations X and Y are polarized relays R R,, R and R, which as shown inthe drawing are arranged in groups of two- The midpoint of the windings 1 and 2 of relay R is connected by conductor 9 to the armature of relay R,. Similarly the midpoint of windings 3 and 4 of relay R, is connected by means of conductor 10 to the armature of the relay R The loop L and the line L, are connected with windings 1 and 3 respectively, and the artificial line networks AL and AL,, adapted to balance loop L and line L, respectively, are connect- 'ed to windings 2 and 4 respectively. Connected with the marking and spacing contacts of relay R are the batteries B and B, i V respectively, and similarly connected to i'elay R, are the batteries B and B, respectively. The Sounders S and S,,-connected in leak circuits of the armatures of the two relays, are designed for nionitoring purposes.

The arrangement of the apparatus at the repeater station Y is similar to that at X. The line L, is connected with winding 5 of relay R and loop L to winding 7 of relay R Artificial lines AL and AL, designed to balance L, and L, respectively are con- The midpoint of windings 5 and 6 is connected by conductor 11 to the armature of R and similarly the midpo nt of windings .7 and 8 is connected by a'conductor 12 to the armature of relay R Batteries B and B, are connected with the marking contacts and batteries B and B are connected with the spacing contacts of relays R, and R, respectively; It is important to point out that the polarity; oi the battery or othersource 100 of a directfcurrent potential normally connected with tlie sub-station end ofthe loop circuits, such as batteries B and B shall be equal and opposite to the polarity of the batterywthntv is connected with the marking 1015 contact of that relay whose armature is connected to. the midpoint of the windings of the relay with which ,the subscribers loop is permanently connected. Thus in the drawing batteries B, and B are represented no as having their positive sides connected-with the loop circuits, and batteriesB and B are represented as having their negative sides connected with the marking contacts of relays R and R respectively.- This is important, since the operation of the system is dependent upon this "principle and the reasons for this will be apparent from a de-'' scription of the manner in which the circuit operates.

The mode of operation of this circuit'is as follows: Let it be assumed that station A is sending and station B. is receiving; that is, key K will be opened and closed-for spacing and marking, and key- K will remain closed for receivin If the key K, is closed to transmit a marking signal, current will flow through the circuit from battery 13,, relay R key K loop 'L winding 1 of relay R conductor 9, marking contact of relay R, and battery B to ground. Current will also flow through winding 2 and the artificial balancingnetwork AL,'. The armature of relay R will be held to the marking contact of this relay since there is an excess of current through winding 1 in a direction to hold the armature in this position.

Since the batteries 13, and B are opposed to each other, no current will flow through the lineL and' the windings 3 and 5 of relays R and R respectively. Current will flow through windings 4 and Get the said relays, but its direction will be such as'to hold the armatures of the said relays against their marking contacts. Since, as has been pointed out, the polarity of battery B is opposite that of battery B current will flow from battery B relay R key K line L winding 7 of relay R, conductor 12, armature of relay R battery B to ground. Current will also flow through winding 8 and artificial lineAL but since the repond'erance. of current flows through win g 7 and is in the direction to hold the" armature of relay R, on its marking contact, the armature 'will so remain. By

the flow of cnrrent' through relay R the marking signal transmitted from station A will be receivedat station E and indicated by the sounder S,.

If the key K be opened to transmit a spacing signal, no current will flow through e winding 1 of relay R but current Wlll flow throughiwinding 2,, and its direction and magnitude willbe suchas to move the armature of the said relay to its spacing contact. Since'batteries B and B are now infconjunction, current will flow from battery B conductor 10, winding 3, line L winding 5, conductor 11, marking contact of relay R and battery B to ground. Current will also flow through windings 4 and 6 of relays R and R respectively. The

magnitude of the current in winding 3 is greater than that in winding 4,, and its direction is such as to hold the armature of relay R upon its marking contact. But the magnitude and the direction of current in winding 5 is such as to'move the armature of the relay R to its spacing contact to which battery B,, is connected. It will be seen that since battery B is in opposition to battery B no current will flow through winding 7 of relay R line L or relay R at station B. Accordingly a spacing signal will be transmitted to station B.

If, during the periodof transmission of signals from station A to station B, the operator at B should break the circuit by would be transmitted to A in the following manner. If at theinstant of breaking, the' operator at A was sending a marking signal, all of the armatures of the polarized relays would be on their marking contacts. The opening of key K will stop the flow of current from battery B through winding 7 of relay R but the How of current through winding 8 will be in such direction and magnitude as to move the armature of the said relay to its spacing contact. Batteries B and B being in conjunction, current will flow through line L and the windings of the relays connected thereto. The armature of relay R, will be held upon its marking contact but the armature of relay R will be moved to its spacing contact. Since batteries B and B, are opposed to each other,

no current will flow over the loop L and in consequence thereof relay R will remain unoperated. This will cause the sounder S to indicate a spacing signal, and, since this is unusual, because the key K is in its marking position, the operator at A will be apprised of the fact that the operator at B is endeavor'ing to get control of the circuit.

From the foregoing itwill be seen that one of the two relays at each repeater point constitutes a non-biasing pole changer, and the other relay of each group constitutes a polarized relay for the proper reception of signals. Thus in Fig. 1, R is a pole changer controlled by' impulses received over the loop L and adapted to apply impulses of the proper polarity to line' L and in turn to relay R which is the polar relay for signals intended to be received at substation B. In transmitting from sub-station B to sub-station A, relay R constitutes a dpole changer controlled by impulses receive over loop L and adapted to impress impulses of the proper polarity upon the line L and relay R, which constitutes for transmitting pole changes, greater eificiency of operation is attainable than was heretofore practicable where neutral relays were utilized for this purpose, in view of fan rea ers caused heretofore by sluggish armature ace tion resulting from residual magnetism of a half duplex repeater with loop circuits.

the neutral relays.

Fig. 2 illustrates ajcombination of the elements shown in'Fig. 1, which constitutes Where loop circuits are located only at terminal stations, the outer end of each of the loop circuits is terminated in a batteryas shown in Fig. 1, and in a manner as described in connection with the said figure.

jWher-e loops are required at a repeater station such as is represented in Fig. 2 by -the loop C, both ends of the line with which the said loop is connected must terminate in duplex sets, such as vare represented at D and E, which together constitute the repeater. In Fig. 2', L represents a telev signals received over the line L, will ac-' graph line circuit extending in one direction from the repeater. station, and L represents a similar line extending also from the same repeater station. L, re resents a circuit for connecting the loop through the repeater with the lines L, and L In this circuit arrangement R, and R, represent pole changers controlled'by lines L, and L respectively, and adapted to impress upon the loop C amplified or repeated signals, in accordance. with impulses received over the lines 1L or L lit, and R,

constitute polar rela s for the reception of signals from lines 8 and L respectively. Thus marking and spacing impulses received over the line L, will cause corresponding movements of the armature of the relay R which will in turn impress upon the loop C and upon relay R marking and spacing impulses. Relay R, will in turn impress upon the line L, corresponding signals. In like manner marking and spacing cordingly operate relay R which will in turn impress marking and spacing signals upon loop C and upon relay R,, which likewise will impress the proper signals upon the line L.

Fig. 3 represents the application of this invention to .a full duplex repeater circuit with loops, which is represented as being ins'erted between sections 1L, and L, of a through telegraph line. This repeater comprises the tour polar relays R R,, R, and Rgthe midpoint-of the windings of relay B, being connected to the armature of relay 3,, and similarly the midpoint of the windings of relay R, being connected to the armature of relay, R The midpoints of the windings of relays R and R are connected directl -With the batteries B, and B respective y, which are ofppposlte polarity. Connected with the sald rela sare the artificial lines AL AL AL, an AL and also the monitoring sounders S 8,, S, and S It is important to note that the.

to be conjunctively related tobatteries B and B respectively. V.

, The mode of operation of this repeater circuit is as follows: When a marking impulse is being transmitted over line-L from a station connected therewith, current will flow through windings 1 and 2 of relayR but its direction will be such as .to maintain the armature of this relay on its marking contact. Currentwill then flow from-the battery B over line L and windings 5 and 6 of relay 3,, and battery B to ground. The direction and magnitude of the current willbe such as to maintain the armature of relay R, upon its marking contact, which causes a flow of current over circuit from battery B winding 7 of relay R and line L, to the station connected therewith. Similarly a spacing signal transmitted from a station connected with the line L will cause a movement of the armatures of relays R and R consecutively totheir spacing positions, and will in turn impress a spacing signal upon line L,. lit the signals are be-.

ing transmitttd by the stations connected I of current in windings 3 and 4 will, he of no such value and in such direction as to hold the armature ot' the said relay upon its marking contact, which will cause the transmission of a marking signal to the line L If a spacin signal is being transmitted over the line 8 at the same time theta marking, signal is bein transmitted over the line L no current wil flow through winding Z of relay R, and the direction of current through winding 8 will be such as to move the armature to its spacing position. Since batteries B and 1B,, are opposed to each other, no current will flow in winding 3 as conductor 1b,. The flow of current in wind- 7 ing 4 will cause the armature of relay 1t,

rto move to its spacing contact, thereby appl ing a spacing signal to the line L y, means of the foregoing arrangement of a duplex repeatercircuit, higher eficiency of operation is attained through the use of polarized relays for pole changers than has.

been heretofore practicable. Although there has been shown at the sub-stations simple Morse apparatus, it is to be understood that any form of telegraph signaling apparatus such as duplex sets might be used, without changing the mode of operation of this invention. Further, although this invention has been shown in certain specific forms, it is to be understood that it is not limited to these-forms, but is capable of embodiment in other and different forms within the scope of the appended claims.

What is claimed is: I

1. In a telegraph signaling system, the combination of two polarized relays having the midpoint of the windings of each relay connected with the armature of the other relay, oppositely poled batteries adapted tobe connected with said armature, a line circuit connected with one'of said polar relays, a loop circuit connected with the other polar relay and having a key, a neutral relay, and a source of potential "associated therewith, the polarity of which is opposite that of the battery normally connected with the midpoint of the windings of that polar relay with whichthe' ,said loop is connected, whereby each polar relay constitutes the pole changer for the transmission of signals from its respective loop circuit.

2. In a telegraph signaling system, combination of polarized relays arranged in groups of two each, the midpoint of the windings of each relay being connected with the armature of the said other-relay, a plurality of sources of potential of opposite polarity adapted to be applied to each of said armatures, a loop circuit connected with one winding and an artificial line connected with the other winding of eachrelay, the said loop circuit comprising a key, a new tral relayand a source of potential,-the polarity ofthe said source being opposite that of the source normally connected with the midpoint of theqwindings of the polar relay with which said loop is connected whereby each of said relays acts as a transmitting pole changer for 'singals transmitted over the loop directly connected thereto.

3. In a telegraph signalingsystem, the combination of two telegraph loops, each having keys -'a neutral relay and a source of potential associated therewith, and a plurahty of polarized relays, the .midpoint of the windings of each relay being connected with the armature of the other of said relays, the said armatures being normally in I the contact witha source of potential, the polarity of which is normally opposite that of the vsource associated with the loop circuit with which the said armature is electrically connected.

4. In a telegraph repeater adapted for half duplex operation, the combination of circuit connected with each group, having associated therewith a source of potential of opposite polarity to that normally connected with the midpoint of the windings of the relay with which said line circuit,

may be connected.

5. In a telegraph repeater circuit, the combination of a plurality ofpolar relays arranged in groups of two each, having sources of current of opposite polarity connected with the marking and spacing contacts respectively of the armatures of each of said relays, and having the windingsof one relay of each group connected with an artificial line and with a line circuitrespectively, and having also the midpoint of said windings connected with the armature of lit) the other relay of the same group, and the windings of the other relay of each group connected respectively with an artificial line and with the armature of the said first mentionedrelay in the other group, and also.

having the midpoint of its windings connected with a source of current the polarity of which is opposite that of the source, normally connected with the marking contact of the armature with which said winding may be connected and a line circiiit connected with the said first mentioned relay of each group and havinga source of potential associated therewith opposite that of the source normally connected with the armature with whichth'e midpoint of the windings of the said first mentioned relays may be connected.

Intestimony whereof, I have signed my name to this specification this 12th day of -March 1920.

JOHN M. FELL; 

